Loud speaker



Aug. 17 1926. 1,596,439

w. LYTTON LOUD SPEAKER Filed March 21 192:5

Patented Aug. 17,4 19,26.

UNITED STATES WALTERl LYTTON, OF CHICAGO, ILLINOIS.

LOUD SPEAKER.

Application med March a1, 1923. serial No. 626,455.

This invention relates to improvements in loud speakers for radio receiving sets, and it has for one of its objects the production of an improved loud speaker, particularly with reference to the relation of the sound reproducer diaphragm of the speaker and the electro-magnetic devices associated therewith. Other objects of the invention will be apparent upon a consideration of 1U the accompanying drawings and the following description thereof.

Of the accompanying drawings, F ig. 1 is an elevation of a loud speaker which embodies the features of my invention; Fig. 2

is an enlarged vertical central section of the same; and Fig. 3 .is a transverse section thereof along the` line 3-3 of Fig. 2.

l The loud speaker comprises a casing 10 and a sound delivering horn 11. Within thecasing isV positioned a magnetic system 12 comprising a central pole 13 and side poles 14, the poles being connected by the magnetic circuit comprising the side bars 15, the base 16, to which the side bars are con= nected in any suitable manner, andthe central post 17. The diaphragm 18 of the loud speaker is composed of any suitable material, but I prefer for the purpose an iron or steel diaphragm; and projectingX from the diaphragm is an armature19 ed to the diaphragm in any suitable manner such as by being .riveted thereto. This armature extends downwardly towards the pole 13.

Between the diaphragm and the` pole` 13 is mounted a coil of wire 20, the terminals 21 of which are adapted to be connected to the output' circuit of a radio receiving sety in the ordinary manner. The magnetic system may be a permanent or an electro-v magnetic system as may be desired. IA prefer for the purpose a permanent magnetic system. The diaphragm is properly mounted on the upper end of thecasing in any suitable manner. I prefer to clamp it between the ring 46 and the annular flange 47 of the cap 48 which is screwed on to the casing 10. l

Asis wellunderstood the audio pulsations of theI output circuit of the receiving system, when the coil 2O is properly con-V nected therewith,v will causejmaterial variations in the current flowing through the coil, and this in turn will cause corresponding variations in the strength of the magnetic field iowing across from the pole 13 -By the arrangement described I provide a' very powerful and sensitive varying electro-magnetic system underneath the diaphragm so'that the pulsations in the coil 20 are transformed into loud' sounds and the sounds produced are not distorted by the producing mechanism. The sound is transmitted from the diaphragm inan ordinary manner through the horn -11.

In order to increasethe power and sensitiveness of the apparatusI provide sensitive and convenient adjusting mea-ns for varying the position of the coil 20, and of the pole 13, with reference to the diaphragm 18 and the armature 19. The' coil is ad justably threaded on to the end of a magnetic bar 22, the upper end of which forms an extension of the pole 13, and thisend 28 may be considered as vthe efective pole. The bar 22 extends downwardly through .the center of the post 17, and its lower end is supported by a thumb screw 23. A

'spring 24 at all times forces the end of the bar downwardly against the screw. Obviously by adjusting the position of the screw 23 with reference to the base 25 of the casing 10 the position of the pole 28 and also of the coil 20 with reference to the.

time the air gap between the two may be reduced to a minimum. And-by adjusting the position of the coil 2O on the end of the bar. 22 the position of 'the coil and the end 28 may be relatively changed with relation 1 to the diaphragm and armature.

In order to reproduce the sounds more nearly normally I provide a horn 11 which comprises the conical standard 26 tothe upper end of which is mounted' the mouth piece 27. In order to produce strength and prevent any. vibrating tendency of the sides I prefer to have the standard made of a metal such as brass. But the mouth piece 27 I prefer to have of a non-metallic material such as vulcanite, as this reproduces the sound more nearly in harmony with .the original sounds.

I claim as my invention:

1. A sound reproducer comprising a magnet having a central post, a Wall surrounding said post, a base connecting said post and wall at their lower ends, a casing surrounding said magnet, a diaphragm mounted in said casing over the up er end of said wall, an armature fixed to t e central ortion of said diaphragm and projecting t erefrom 'towards said post, all of said elements being composed o' magnetic material; in combination with a coil surrounding said armature and positioned above the upper end of said post, the terminals of said coily being adapted to be connected with the output circuit of ay radio receiving set.

'2. A sound reproducer comprising a ma net having a central post, a wall surroun ing said post, a base connecting said post and wall at their lower ends, a casing surrounding said magnet, a diaphragm mounted in said lcasing over the up er end of said Wall, an varmature fixed to t e centrai ortion of said diaphragm ,and projecting t erefrom towards said post, all of said elements being composed of ma netic material; incombination with a coi surA rounding said armature and positioned above the upper end of said post, the terminals of said coil being adapted to be connected with the output circuit of a radio receiving' set, the upper end ci said post passing into said coil.

3. A sound reproducer comprisinga magnet having a central post, a Wall surroundling said post, a base connecting said post and wall at their lower ends, a casing surrounding said magnet, a diaphragm mounted in said casing over the upper end. of said wall, an armature hired to the central portion of said diaphragm and projecting therefrom towards said post, all of said elements being composed of magnetic material; in combination with a coil surrounding said armature and positioned above the upper end of said post, the terminals of said coil being adapted to be connected with the output circuit of a radlo receiving set, and a member slidably mounted in said post, and projecting slightly into said coil.

4. A sound reproducer comprising a magnet having a central post, a wall surrounding said post, a base connecting said post and Wall at their lower ends, a casing surrounding said magnet, a diaphragm mount-i ed in said casing over the upper end of said wall, an armature Xed to 'the central portion of said diaphragm and projecting therefrom towards said post, all of said elements being composed of magnetic material, the upper end oi said post comprising member slidably mounted in the main portion of said post, and means for adjusting the position of the upper end of said post with reference to said armature, saidcoil being threaded onto the upper end of said slidable member.

5. A sound reproducer comprising a mage netic circuit consisting of a central post, a side Wall, and a base connecting said post and wall, a, diaphragm mounted on the upper end of said wall, and a member mounted for relative longitudinal movement in said post, all of said elements being composed of magnetic meaterial, and a coil fixed to the upper end of said slidable member and positioned adjacent said diaphragm, the terminals of said coil being adapted to be connected to the output circuit of a radio receiving set.

6. A sound reproducer comprising a magnetic circuit consisting of a central post, a side wall, andv a base connecting said post and Wall, a diaphragm mounted on the upper end of said Wall, and a member mounted for relative longitudinal movement in said post, all of said elements being composed of magnetic material, and a coil lfixed to the upper end of said slidable member and positioned adjacent said diaphragm, the terminalsof said coil being adapted. to be connected to the output circuit of a radio receiving set, and an armature said diaphragm and into said coil.

7 A sound reproducer comprising a magnetic circuit consisting of a central post, side Wall, and a base connecting said post and iwall, a diaphragm mounted on the upper end of said wall, and a member mounted for relative longitudinal movement in said post, all of said elements being composed of magnetic material, and a coil xed to the upper end of said slidable member and positioned adjacent said diaphragm. the terminals of Said coil'being adapted to be connected to the output circuit of a radio receiving set, and an armature projecting downwardly from the centra-l portion oi' said diaphragm and into said coil, and means' for adjusting the position of said slidable member with reference to said armature.

8. A sound reproducer comprising a casing, a magnet mounted in said casing and having its two poles adjacent the upper end thereof, a sound reproducer diaphragm mounted adjacent the ends of said 'two poles with its central portion adjacent one orp said poles, a member mounted for relative longitudinal movement in said latter pole, means for varying the. strength of `the magnetic field between said poles, and means projecting downwardly from the central portion ot" Mill) for adjusting theposition off said member bottom of said casing and projecting up wardly into said post, theI lower end ofsaid v slidable member being'posit'ioned Aon the end thereof, a sound reproducer diaphragm' mounted adjacent the ends of said two` poles with its central portion adjacent one of said poles, a member mounted.- for relative longitudinal movement in said latter pole, means for varying the strength of the magnetic field between said poles, and means for ad'usting the position of said member with re erence to said diaphragm, said means comprising a screw threaded into the bottom of said casing and projecting upwardly into said post, ythe lower end of said slidable member being positioned on the upperY end of said screw, anda spring positioned in said post arranged to continuously press said slidable member downwardly ontosaid screw.

In testimony whereof, I hereunto set `my hand.

WALTER LYTTON. 

